Enum RenderError 

#[non_exhaustive]
pub enum RenderError {
    #[non_exhaustive]
    MissingModule {
        route: String,
    },
    #[non_exhaustive]
    Walk {
        route: String,
        component_path: Vec<String>,
        counts: RenderCounts,
        cause: IrError,
    },
    #[non_exhaustive]
    Policy {
        route: String,
        cause: PolicyError,
    },
    #[non_exhaustive]
    Nonce {
        route: String,
        cause: NonceError,
    },
    #[non_exhaustive]
    Budget {
        route: String,
        component_path: Vec<String>,
        counts: RenderCounts,
        cause: IrError,
    },
    #[non_exhaustive]
    Fault {
        route: String,
        component_path: Vec<String>,
        counts: RenderCounts,
        message: String,
    },
}

Why a page was not rendered. Nothing reaches the browser unless the handler sends it: answer with the application’s own error page.

Every error has a stable code, the route it was rendering, and the component_path where it stopped (empty when the failure is not inside a component). The codes, by family:

Code	Variant	Cause
RENDER-101	MissingModule	The config has no module or no slots to render
RENDER-102	Walk	The walk refused the module or its data
RENDER-201	Policy	A policy extension is not a source a page may add
RENDER-202	Nonce	The system random source failed to draw a nonce
RENDER-301	Budget	The walk’s output passed max_output_bytes
RENDER-302	Budget	The walk’s list rows passed max_list_iterations
RENDER-303	Budget	Lists or control flow nested past the walker’s depth
RENDER-399	Fault	The render panicked; a defect, not an input

A code, once published, keeps its meaning; new causes get new codes.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

#[non_exhaustive]

MissingModule

RENDER-101: try_render renders on the server, and the config carries no module or no slots for it. A browser-rendered route is served by render_browser_shell, by declaration.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

route: String

The route being rendered.

#[non_exhaustive]

Walk

RENDER-102: the walk refused the module or the data it was given.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

route: String

The route being rendered.

component_path: Vec<String>

The islands open where the walk stopped, outermost first.

counts: RenderCounts

How far the walk got.

cause: IrError

The walker’s error.

#[non_exhaustive]

Policy

RENDER-201: a policy extension was refused; there is no page to send without its policy.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

route: String

The route being rendered.

cause: PolicyError

The refused extension.

#[non_exhaustive]

Nonce

RENDER-202: no nonce could be drawn, so no policy could bless the page.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

route: String

The route being rendered.

cause: NonceError

The failed draw.

#[non_exhaustive]

Budget

RENDER-301, RENDER-302, RENDER-303: the walk reached one of its budgets, and stopped there instead of running on.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

route: String

The route being rendered.

component_path: Vec<String>

The islands open where the walk stopped, outermost first.

counts: RenderCounts

How far the walk got before the budget stopped it.

cause: IrError

The budget the walker reports.

#[non_exhaustive]

Fault

RENDER-399: the render panicked and the panic was caught. The process and every other request carry on, while the application unwinds on panic; under panic = "abort" the process ends.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

route: String

The route being rendered.

component_path: Vec<String>

The islands open where the walk panicked, when it was in the walk.

counts: RenderCounts

How far the walk got, when it was in the walk.

message: String

The panic’s message.

Implementations

impl RenderError

pub fn code(&self) -> &'static str

The stable code, such as RENDER-301.

pub fn route(&self) -> &str

The route pattern the render was for.

pub fn component_path(&self) -> &[String]

The component names of the islands open where the render stopped, outermost first; empty when it stopped outside every island or before the walk. A component the compiler inlined into its parent has no name until FMIR v3’s source positions.

pub fn counts(&self) -> Option<RenderCounts>

How far the walk got, for an error raised during it.

Trait Implementations

impl Clone for RenderError

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RenderError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for RenderError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for RenderError

impl Error for RenderError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for RenderError

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for RenderError